Development of a normal tissue complication probability model for dysphagia in PATHOS trial patients

Higgins, Emma 2025. Development of a normal tissue complication probability model for dysphagia in PATHOS trial patients. MD Thesis, Cardiff University. Item availability restricted.

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Abstract

Dysphagia (swallowing dysfunction) is a common and debilitating consequence of head and neck (H&N) cancer treatment, which substantially impacts a patients’ quality of life (QOL). This is of particular relevance in HPV+ve oropharyngeal squamous cell cancer (OPSCC). These patients are typically younger and fitter, and have a better prognosis than patients with HPV-independent H&N cancer, therefore will live longer with the side-effects of their treatment. Highly conformal radiotherapy (RT) techniques, increase the flexibility of dose deposition, allowing dose reductions to Swallowing Organs-at-Risk (SWOARs) in an effort to minimise dysphagia. Normal tissue complication probability (NTCP) models, developed using multivariable logistic regression modelling, describe the relationship between significant dosevolume parameters and risk of dysphagia. However, these models have mostly been developed in H&N cancer patients undergoing definitive RT or chemo-radiotherapy (CRT), rather than in patients undergoing surgery and adjuvant RT or CRT. The first part of this thesis evaluates on-trial SWOAR delineation to determine if inter-observer variation impacts NTCP values. This is important in context of highly conformal treatment with steep dose gradients where optimising radiotherapy plans to SWOARS requires accurate and consistent delineation to fully realise the benefit of sparing these structures. The next part of the thesis examines existing NTCP models for dysphagia and assesses the performance of an established dysphagia model in PATHOS patients undergoing adjuvant radiotherapy, demonstrating that it did not perform well in this cohort. In the final part of this thesis, a new NTCP model is developed using the MD Anderson Dysphagia Inventory (MDADI) as a measure of dysphagia, to establish for the first time the pertinent dose-volume parameters associated with dysphagia in patients who undergo transoral surgery followed by adjuvant RT. This model could be further developed and used to facilitate individualised treatment planning to improve long term functional outcomes and QOL in these patients.

Item Type:	Thesis (MD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Medicine
Date of First Compliant Deposit:	27 June 2025
Last Modified:	27 Jun 2025 14:25
URI:	https://orca.cardiff.ac.uk/id/eprint/179369

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